(a) Field of the Invention
This invention relates to a cap mounting arrangement in which a cap with a sealing member is detachably attached to a container to hermetically closes an opening of the container.
(b) Description of Related Art
Cap mounting arrangements of this type have conventionally been used, for example, for oil caps for engine oil filling provided on cylinder head covers in automobile engines. These oil caps are generally of a screw type which is fitted with an O-ring as a sealing member and closes an opening of a cylinder head cover by screwing internal threads formed on the opening of the cylinder head cover with external threads formed on the oil cap.
For example, a cap mounting arrangement in which a cap opens/closes an opening serving as an engine oil inlet is disclosed in Japanese Unexamined Patent Publication No. 2003-81316 (page 2 and FIG. 1). The cap is of a screw type formed of a plug having external threads on its outer periphery and a flange formed at one end of the plug. The cap opens or closes the opening by turning the flange grasped with one hand to screw the plug into or out of the opening.
In hermetically closing the opening with the cap in the above cap mounting arrangement, however, the plug cannot be screwed into the opening unless the external threads of the plug are properly mated with the internal threads of the opening. In such a case, the need is to detach the plug from the opening and try the closing (plug turning) again, which deteriorates workability. Further, when the cap has been tightly screwed on in order to avoid oil leakage through the opening, it is difficult to screw off the cap and a strong turning force is needed for cap removal.
In the meantime, resin molded articles have been dominating as cylinder head covers and oil caps for the purpose of weight reduction or other purposes. With resin molded articles, the internal threads on the inner surface of the opening have undercut profiles when molded, which produces the need for using a mold having a sliding platen or a rotating platen. This results in raised mold cost.
Therefore, there is a need for a cap mounting arrangement in which a cap with a sealing member can open and close the opening of a container without providing internal and external threads as described above.
A known cap mounting arrangement in which a cap is inserted into an opening without providing internal and external threads is disclosed, for example, in Japanese Unexamined Patent Publication No. 2002-106530, though it is different in use from the first-mentioned cap mounting arrangement. In this arrangement, a mounting member for fixing a part to a vehicle body is formed with engaging holes and a slit extending in an axial direction, and a cap insertable into the mounting member is provided with engaging extensions for the engagement with the engaging holes and an engaging pin insertable into the slit. In mounting the cap to the mounting member, the engaging pin is engaged with the slit at its intermediate part so that the cap can be prevented from undesirably getting out of the mounting member.